elsewhen - 7:12 pm on Jul 15, 2011 (gmt 0)
I can't imagine placing low-quality articles on a separate subdomain. That just seems like more of a mess to me
in the case of UGC sites that have content from all sorts of contributors, it is difficult for them to know what google considers high quality and low quality. panda openly throws out the baby with the bathwater (see "low quality content on one part of your site, can negatively impact high quality content elsewhere on your site.")
in the case of hubpages, they are separating content by author - some of which are probably great, and some of which are probably terrible. the really good stuff, should get linked to more, get more social shares, and should get better user-engagement, and probably has better results on anything else panda cares about. why wouldn't google feel confident about sending it's users to those subdomains?